A system is said to be ______, if its output is under control
Understanding the behavior of a system's output is fundamental in many fields, including engineering and control theory. The question asks about the characteristic of a system whose output remains "under control".
System Output and Control
When we say a system's output is 'under control', it generally means that the output signal does not grow without bound over time. Instead, it remains within certain limits or settles to a specific value, even when disturbances are applied or when the system is given an input.
Defining a Stable System
A system is considered stable if, for any bounded input, its output is also bounded. In simpler terms, if you give a stable system an input that doesn't go to infinity, its output won't go to infinity either. This is precisely what is meant by the output being 'under control'. A stable system's response remains within limits.
Let's consider the other options:
- Unstable: An unstable system is the opposite of a stable system. For a bounded input, the output of an unstable system grows without bound. This means the output is definitely not under control.
- Constant: A constant output is a specific type of output, but it's not the definition of 'under control'. A system can have a non-constant but still bounded and controlled output (e.g., oscillating within limits or settling to a non-zero value). A constant output is a special case that occurs under certain conditions in a stable system (like steady-state response to a constant input).
- Flexible: Flexibility typically refers to a system's ability to adapt or handle variations in inputs or conditions. While a flexible system might be designed to handle a range of operations, this term does not directly describe whether its output remains bounded or 'under control' in the technical sense of stability.
Therefore, a system whose output is under control is best described as a stable system because stability guarantees that the output remains bounded and does not run away to infinity, keeping it manageable and 'under control'.
Important Questions from Basics of Control Systems
- Match the LIST-I with LIST-IIChoose the correct answer from the options given below:
LIST-I LIST-II A. Nyquist Criterion I. Polar Plots B. Bode Plot II. Rectangular Plots C. Phase Margin III. Amount of additional phase lag at the gain crossover frequency required to bring the system to the verge of instability D. Gain Margin IV. It is the reciprocal of the magnitude $|G(j\omega)|$ at the frequency at which the phase angle is $-180^\circ$. - Which of the following statement is not correct in respect of Transfer Function of linear Time Invariant System
A. In any open loop control system, the output is not compared with the reference input.
B. Traffic control by means of signals operated on a time basis is an example of closed loop control.
C. Closed loop control always implies the use of feedback control action in order to reduce system error.
D. Washing machine is an example of open loop system.
E. Stability is a major concern in open loop control system.
Choose the correct answer from the options given below:
Read the following statements about the transfer function of a system :
(a) The transfer function provides complete insight into the structure of the system.
(b) It offers a symbolic picture about the dynamic characteristics of the system.
(c) It does not give any insight into the structure of the system.
(d) If the transfer functions of individual components of the system are known, the overall characteristics of the system can be determined just by taking their product.
Which of the above statements are correct ?
The mass-spring-damper system shown in the following figure represents :
